In communication networks, and in particular wireless communication networks, coordination is required between communicating devices. The coordination is managed by a network controller which sets the parameters for each device to use to avoid communication collisions or cross-talk.
In a downlink (DL) transmission the access point (AP) is both the data originator and network controller. Accordingly, the AP has control over the communication as it is both the controller and the point of transmission to listening STAs.
In an uplink (UL) transmission, however, the AP only acts as the network controller and the STAs are the data originators. In order to coordinate the STAs transmissions, the IEEE 802.11ax draft standard proposes that the AP may exercise UL control via the use of trigger frames that are sent to STAs. Upon receipt, each STA may process a received trigger frame to obtain the communication protocol to be followed. That STA may then apply the protocol when transmitting data to the AP, or in some cases to other STAs.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.